Door interlock for washing apparatus



June 11, 1968 E. s. PROSSER ET AL 3,387,873

DOOR INTERLOCK FOR WASHING APPARATUS Filed Maren 29, 1967 2 Sheets-Sheet 1 A. 7 Q i-5 June 11, 1968 E. s. PROSSER ET AL 3,387,873

DOOR INTERLOCK FOR WASHING APPARATUS Filed March 29, 1967 m at Unite States Patent 3,387,873 DOOR INTERLOCK FOR WASHING APPARATUS Eric Stuart Presser, Merthyr Tydfil, and William Grayham Hall, Caerphilly, Glamorgan, South Wales, assignors to The Hoover Company, North Canton, Ohio, a corporation of Delaware Filed Mar. 29, 1967, Ser. No. 626,819 Claims priority, application Great Britain, Mar. 31, 1966, 14,342/ 66 Claims. (Cl. 292175) ABSTRACT OF THE DISCLOSURE A mechanical interlock for the loading door of a washing apparatus having a reciprocally mounted member arranged for movement between locking and release positions by which the door latch is permitted to move to allow opening the door, the reciprocally mounted member extending from a lever operated by a handle for the door latch to a region Where a pivotally mounted part is arranged normally to prevent reciprocal movement but is controlled by a cam on the washer program timer to permit opening of the door. The pivotally mounted part controlled by the timer cam also operates a washing program indicator.

Background of the invention This invention relates to washing machines and while the invention is particularly applicable to a laundry machine for washing and/or spin drying clothes, it is also applicable to other forms or" washing machines, such as dish-washing machines.

The invention is principally concerned with aspects of safety of a Washing machine. Modern Washing machines which employ either fast rotating parts or washing liquids at high temperatures require extremely caref-ul design if it is to be ensured that serious hazards such as scalding or the touching of fast rotating parts is to be avoided. These hazards are particularly applicable to washing machines provided With a door through which the articles to be washed can be loaded or unloaded especially where this door is in a position accessible to children and, therefore, at the present time washing machine manufacturers are concerned with providing the very best possible safety devices to avoid these hazards. In providing these safety devices various considerations have to be borne in mind. For example, an over-riding consideration is the infallibility of the safety device but at the same time wherever possible producing arrangements which are simple and robust.

Summary According to the present invention a washing machine includes a loading door for loading and unloading articles to be washed into a container, a timer for timing 8. cycle of operations of the machine during which the container is, at certain periods, in a state where opening of the door would be dangerous or unwise, mechanical interlock means being provided between a door latch and the timer, the interlock means cooperating with the timer so as to prevent opening of the door while the machine is in that state but permit such opening at other periods.

According to a specific arrangement a washing machine includes a loading door for loading and unloading articles to be washed into a container, a timer for timing a cycle of operations of the machine during which the container is at certain periods containing water which is at a level above the lower edge of the door, mechanical interlock means being provided between a door latch and 3,337,8?3 Fatented June 11, 1968 "ice the timer, the interlock means cooperating with the timer so as to prevent opening of the door during said certain periods but permit such opening at at least one other period either during or after completion of the cycle and at which the water level is below the lower edge of the door.

According to a further aspect a washing machine includes a loading door for loading and unloading articles to be washed into a container, a timer for timing a cycle of operations of the machine during which a part of the machine which is accessible if the door is open is rotating at certain periods, mechanical interlock means being provided between a door latch and the timer the interlock means cooperating with the timer so as to prevent opening of the door during said certain periods but permit such opening at at least one other period at which the said part of the machine is not rotating.

Preferably an over-ride control is provided which requires the use of a tool to permit opening of the door at a stage when the interlock means is normally preventing its opening. This enables access to be had to the washing machine in the event of a break down at that stage.

Conveniently the mechanical interlock means includes a reciprocally mounted member arranged for movement between locking and release positions at which the door latch is respectively prevented and permitted to move to allow opening of the door, the reciprocally mounted member extending from a lever operated by a handle for the door latch to a region where a movably mounted part is arranged normally to prevent reciprocal movement but to be capable of actuation by the timer, when opening of the door is to be permitted, thereby to permit such reciprocal movement.

For this purpose the timer may have a cam arranged to operate a cam follower carried by a pivotal arm having a part arranged to prevent opening of the door, this pivotal arm being biased to a position at which opening of the door is permitted.

A particularly convenient arrangement embodies a program indicator which is also operated by the pivotal arm, the program indicator incorporating a spring which returns the indicator and the arm at the end of a washing cycle to an initial position at which the arm permits opening of the door.

Description of the drawings The invention may be carried into practice in various ways but one specific embodiment will now be described by way of example With reference to the accompanying drawings in which:

FIGURE 1 is an elevation of part of a door timer interlock mechanism for a washing machine as viewed from within the machine;

FIGURE 2 is a side sectional elevation on the line 22 of FIGURE 1;

FIGURE 3 is an enlarged elevational View of part of the interlock mechanism;

FIGURE 4 is a plan view of the parts shown in FIG- URE 3;

FIGURE 5 is a plan view showing in outline a timer for the washing machine, an arm operated by the timer and a program indicator operated by the arm;

FIGURE 6 is a front elevation, partly broken away, of the mechanism shown in FIGURE 5, and

FIGURE 7 is a perspective view of a typical clothes Washing machine showing the clothes loading door, door handle and program indicator.

Description of the preferred embodiment FIGURES l, 2 and 7 illustrate a front wall It) of the outer casing of a horizontal axis drum-type washing machine which is loaded through an opening in the wall 10 which is normally closed by a door 11 hinged about a vertical axis. The door is capable of being locked in its closed position by means of a horizontally movable bolt 12 which is actuated by means of a door handle 13 on the exterior of the front wall 10, the handle 13 being secured to a shaft 14 which has keyed to it a bell-crank 15, a vertical arm 17 which has a projection 18, shown in FIGURE 2, extending into a slot 29 in the bolt 12. Thus, counterclockwise rotation of the bell-crank as shown in FIGURE 1 will cause the bolt to be withdrawn to allow the door 11 to be opened. The bolt 12 is biased to its locking position by a spring 22.

The bell-crank 15 also has a generally horizontal arm 23 having a fiat upper face extending upwardly from the end of which. is a vertically mounted interlock rod 24 mounted for reciprocal movement in brackets 25 and 26. The rod is biased downwards by a spring 27. While the rod 24 is capable of movement from the position shown in FIGURE 1 to make opening of the door possible, if the rod 24 is held against vertical movement it will be appreciated that rotation of the bell-crank 15 and opening of the door will not be possible. Such. a circumstance is obtained by the provision of a horizontal arm 30 mounted, as shown in FIGURE 3, for rotation about a vertical axis in a bracket 31. A coil spring 32 is provided for biasing the arm 30 to a position in which its end 33 overlies the upper end of the rod 24 as shown in FIGURE 1.

As shown in FIGURES 3 and 4 the arm 3t? has secured to it a cam 34 (also shown in FIGURES l and 2) which is arranged to cooperate with a pivoted lever 40 formed in two sections riveted together at 40A (see FIGURE The lever 40 is pivotally mounted at 41 on the underside of a timer 42 which is employed for timing a cycle of operations of the washing machine. The timer is driven by a separate motor of well known construction.

As shown in FIGURE 5 the timer 42 has a main timing cam shaft 43 which projects downwards from the underside of the casing of the timer and this has secured to it an interlock indicator cam 44. Cooperating with the cam 44 is a cam follower 45 mounted on the end of the pivoted lever 40 adjacent the cam 44.

When the washing machine commences its cycle of operations the cam 44 progressively rotates in a counter clockwise direction and so moves the lever 40 also in a counterclockwise direction as viewed in FIGURE 5 thereby moving its free end remote from the timer away from the cam 34 so that the spring 32 can move the arm 30 to a position in which vertical movement of the rod 24 is prevented. At the end of the washing machine cycle the cam follower 45 will return down the radial face 47 of the cam to permit the arm 44 to return to the position shown in FIGURE 5 at which its free end is biased (in a manner which will be referred to) against the cam 34 to move the end 33 of the arm 30 out of line with the upper end of the rod 24 so permitting opening of the door.

As shown in FIGURE 2 the end of thelever 40 remote from the timer 42 has a generally vertical portion 50 merging with a generally horizontal portion 51 the edge of the latter portion being that part of the arm which cooperates with the cam 34.

Projecting forwards from the generally vertical portion 50 is an L-shaped bracket 53 which, as shown in FIGURE 5, carries at one end a small pulley 54 around which extends an indicator string 55. As shown in FIGURE 5 one end of this string is secured to a stationary bracket 56 and the string extends from this bracket to the right as viewed in FIGURES 5 and 6 thence around the pulley 54 and back through a longitudinal channel 57 to a further pulley 58. The string, as shown in FIGURE 6, then extends to a pulley 59 secured to one end of a coil spring 52 the other end of which is secured to the machine at 61. Finally the string extends from the pulley 59 to a further stationary bracket 60. The run of the string between the pulley 54 on the lever 40 and the pulley 58 is secured to an indicator slide 62 by means of a pair of clamping lugs 63. The indicator slide 62 is guided for horizontal movement by means of the longitudinal channel 57.

As indicated in FIGURE 6 the front face 66 of the washing machine is provided with a rectangular opening 67 behind which the indicator slide 62 moves so that its forward edge 68 gradually moves to the right in FIG- URE 6 as the program progresses to give an indication of the stage at which the program has reached at any given time. For this purpose the front face of the indicator slide 62 may be painted a prominent color such as red and the various stages of the program marked along the front face 66 of the machine.

It will be appreciated that by providing the three pulleys 54, 58 and 59, as the lever 40 is moved in a counterclockwise direction, as viewed in FIGURE 5, by the interlock indicator cam 44, the string 55 will be drawn to the right, the length of string being drawn through the channel 57 being twice the extent of movement to the right of the pulley 54 on the lever 40. In this way the extent of movement applied by the end of the lever 40 to the indicator slide 62 is magnified and in practice the forward edge 68 upon full movement of the lever 40 to the right, i.e. at the end of the program, will be adjacent the right hand end of the rectangular opening 67 in FIGURE 6.

The third pulley 59 carried by one end of the spring 58, on the other hand, is drawn to the left to an extent substantially equal to the movement to the right of the pulley 54 so that the spring 52 is only extended to an extent substantially equal to the movement of the lever 40. The spring 52 acts as a return spring biasing the arm 40 in a clockwise direction, thereby maintaining the cam follower 45 in engagement with the surface of the cam 44 and ensuring return of the parts to the position of FIGURE 5 at the end of the program. The spring 52, therefore, has the further function of providing the bias required on the lever 40 to cause it to act on the cam 34 to move the end 33 of the arm 30 out of line with the upper end of the rod 24 to permit opening of the door of the washing machine. In this way, therefore, a single arm operated by a cam of the timer is employed for two purposes; namely, to provide an interlock with the door of the washing machine and also to operate the indicator mechanism.

The lever 40 which is actuated by the timer 42, as

has already been mentioned, only bears on the cam 34 to permit opening of the door at the end of the washing program and, therefore, it is impossible for the door to be opened at any time during the program, thereby avoiding any possibility of a door being opened at a time when the machine may be full of hot or near boiling water at a level above the door. In practice, in order to be absolutely certain that the rotary parts of the washing machine which may, for example, include a drum for rotation about a horizontal axis, are stationary at the time when the lever 40 bears on the cam 34, the program of the washing machine preferably includes a period at its end which does not involve any rotation of the drum. For example, the program could include a one minute pumping period as the last stage of the program to ensure that the drum will have slowed down and stopped if the period before this pumping period is a spinning operation. By this arrangement it is unnecessary to provide a brake for the drum. It can simply be allowed to come to rest in its own time since there is no danger of the door being opened before an appreciable time has elapsed after the spinning operation. This avoids the provision of a brake and associated mechanism for example, a linkage with the door of the washing machine which is a fairly conventional but complicated arrangement in this kind of washing machine.

By virtue of the interlock arangement, opening of the door without moving the rod 24 into its raised position is impossible. In the event, therefore, of a mechanical or electrical failure in the washing machine itself or a power failure causing the machine to stop before the end of the program and, therefore, before the lever 40 has acted on the cam 34 to permit the rod to rise it could be that the machine will stop in the middle of the program. In order to permit opening of the door in such circumstances an over-riding control may be provided which requires the use of a tool. For example, referring to FIGURE 1 a reciprocally mounted member (69) may extend from adjacent the cam 34 in a horizontal manner (to the left in FIGURE 1) to position adjacent the outer casing of the washing machine. By providing a small hole in the casing in line with this member but ensuring that the member does not reach the hole it would be possible to insert a tool, such as a screw-driver, to move the member towards the cam 34 to rotate the arm 30 to a position in which upward movement of the rod 24 and opening of the door is possible. It is to be understood that this over-ride control is not operable without the positive use of a tool and is only intended to be operated under abnormal conditions of operation. It is also to be understood that this over-ride mechanism is only one example of possible mechanisms which could be provided and even more stringent safeguards could be provided if desired. For example, it might be advisable to necessitate the unscrewing of some form of cover from over the hole prior to the insertion of the tool.

It is also to be understood that where provision needs to be made for opening the loading door of the machine during a program cycle, but not during the dangerous period referred to, the cam 44, for example, can be contoured appropriately to permit this to occur.

Although only one embodiment has been shown and described, the present invention includes all equivalent variations of the embodiment disclosed and is limited only by the scope of the claims.

We claim:

1. In a washing apparatus including a door for loading and unloading article to be washed, a timer for timing a cycle of operations, a mechanical interlock means between a door latch member and said timer comprising a reciprocally mounted member extending from a crank lever operated by a handle for said door latch member, a blocking mechanism to prevent movement of said reciprocally mounted member, a pivoted lever having a follower pin to engage a cam on the shaft of said timer and cooperating with said blocking mechanism to restrict the movement of said reciprocally mounted member to prevent said door from being opened during certain periods.

2. The device of claim 1 wherein the washer apparatus includes a program indicator which is operated by said pivoted lever.

3. The device of claim 1 wherein said door latch member is spring biased to a latched position.

4. The device of claim 1 wherein said reciprocally mounted member is spring biased to engage said crank lever on said door handle.

5. The device of claim 1 wherein said blocking mechanism comprises a pivoted arm which is operated by said pivoted lever to block the movement of said reciprocally mounted member.

6. The device of claim 5 wherein said pivoted arm is spring biased to a door locking position.

7. The device of claim 5 wherein a separate control member extends from an opening in the wall of said washing apparatus and cooperates with said pivoted arm for release of said pivoted arm from blocking position and overrides the interlock mechanism in case of a mechanical or electrical failure in the washing apparatus.

8. The device of claim 5 wherein the end of said pivoted lever opposite said follower pin has a generally vertical portion merging with a generally horizontal portion, the edge of said horizontal portion being that part of the pivoted lever which engages said pivoted arm.

9. A washing machine including a door for loading and unloading articles to be washed in a container, a timer for timing a cycle of operations of said machine during which said container is at some periods in a state where opening said door would be dangerous, a program indicator device, a mechanical interlock means between a door latch member and said timer comprising an interlock rod extending from a crank lever operated by a handle for said door latch member, a blocking device to prevent movement of said interlock rod, a pivoted lever having a follower pin to engage a cam on the shaft of said timer and cooperating with said blocking mechanism to permit opening said door only when said washing machine is in a safe condition, said pivoted lever also operating said program indicator.

10. The device of claim 9 wherein said blocking mechanism comprises a pivoted arm which is operated by said pivoted lever to block the movement of said interlock rod.

References Cited UNITED STATES PATENTS 2,896,641 7/1959 Kaufiman et al. l34-58 MARVIN A. CHAMPION, Primary Examiner.

ROBERT L. WOLFE, Assistant Examiner. 

